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June, 1917 those of a steel ship, but by proper design and construction a great deal of the weakness inherent in wooden hulls may be overcome. -If we con- sider a ship as a beam and resort to the language of the engineer for a moment, we find that the greatest strength should be concentrated as far from the neutral axis (approxi- mately the center of the load water- line plane) as possible; also, the sides of the vessel should be designec to withstand permanent vertical and longitudinal stresses; and the connec- tions between the flange and web members (decks and sides) should be as rigid as possible. Typical Wooden Vessels The accompanying cross sections of typical wooden ships show how de- signers in various parts of the world and at different times have attempted to meet these conditions. Fig. 3 shows the cross section of an English sailing ship built to rigid specifications about 1850. This vessel was 30 feet beam and about 180 feet in length. A detail of the keel con- struction is shown in Fig. 2. This ship had considerably more deadrise than a modern cargo carrier, that is her bottom was much less flat than is now customary, and this rounded construction added tremendously to her strength. she had In addition, Glia CA Pe t- LE LLL NA Lh | Al k D y OUTSIDE ju L d “ “ PLANKINGSE NEN 02 X/5z ,) PI pg SS EES 9 4 rea Bears 83'x /43"-350"€¢-s | NB | cert _ NE aa it y) = & a = 4 SS 7) | ] 9 s “ % BILGE CEILING 5g 178'% 178 BILGE PLANHING H.\\\ af Pin (aes. RAIMES DOUBLE 7%" FIR-5O"E-S — SS t ONE ExTRA FLOOR ACROSS BOT TOI 7 SIDED. 5 A = ALONGSIDE EACH FRA Of be, Artib- ‘| | BLS 1 Ss TY SHIES os = OSSSIN ES a Soe see = 9; DOUBLE DIAGONALS ToTAL 25" ne apd, LAG ISS pL Bor Tor PLANKING 487, Surg? S ») 3 /9-0*- TEXTS" THE MARINE REVIEW S : Gea Hf FIG. 5—MIDSHIP SECTION 197 at KY Sy) TW MIs OF A MODERN AMERICAN WOODEN SHIP OF THE CONVENTIONAL TYPE two decks, the lower deck beams _ be- ing 6% x 8 inches and the main deck beams 9 x 10 inches. Finally, she was:very carefully and painstak- ingly fitted together in order to give the utmost stiffness and permanency to the hull structure. Fig. 5 shows a cross section of a modern Pacific coast lumber vessel of the conventional type. It forms an interesting comparison with Fig. 3. This ship is 48 feet beam and about 275 feet in length. Her floors are 18 | HATCH Coartine 20° /16H | aes iu | BEAMS 62" Si0E 0-30" E-5 STRINGERS 5 X10" PEG. 4—MIDSHIP SECTION OF A WOODEN SHIP DESIGNED BY A MODERN PACIFIC COAST NAVAL ARCHITECT inches deep, compared with 914 inches in the English ship shown in Fig. 3. But in the latter case, natural bent oak was used for the frames and in the modern Pacific coast boat, sawn fir. Some architects think that the depth of the frames in the _ vessel shown in Fig. 5 is too small. This illustration, however, shows very clearly the characteristics of cus- tomary American construction. The feature of the design is the large number of keelsons, nine in all, run- ning from stem to stern like a small mountain range. Fig. 5 also indi- cates the large size of the planking and ceiling timbers. A more advanced form of construc- tion, designed by Fred A. Ballin, naval architect, Portland, Ore., is shown in Fig. 4. In this case the necessity for a large number of keel- “sons is obviated, in the designer’s opinion, by the use of deep floors and deck beams. Care also is taken in the disposal of the knees, ceiling and planking. How. Steel is Used One of the most successful forms of steel reinforcement for wood ves- sels is shown in Fig. 6, illustrating a method of construction patented by Frank E. Kirby, of Detroit, one of the most famous naval architects on the Great Lakes, where a large num- ber of unusually staunch wooden ves- sels were built in the era before the steel freighter. According to Mr. Kirby’s patent, the topsides are strengthened by means of a steel sheer plate, to which. a deck stringer plate is connected with a strong angle. The deck stringer rests directly on the top of the top timbers of the frames and the iron straps running diagonally around the hull are fast- ened to the sheer plate. This is somewhat similar to the method of reinforcement adopted for the new